1. Field of the Invention
This invention pertains generally to imaging, and more particularly to ultrasound imaging using a synthetic aperture ultrasound waveform tomography.
2. Description of Related Art
Breast cancer is the second-leading cause of cancer death among American women. The breast cancer mortality rate in the U.S. has been flat for many decades, and has decreased only about 20% since the 1990s. Early detection is the key to reducing breast cancer mortality. There is an urgent need to improve the efficacy of breast cancer screening. Ultrasound tomography is a promising, quantitative imaging modality for early detection and diagnosis of breast tumors.
Ultrasound waveform tomography is gaining popularity, but is computationally expensive, even for today's fastest computers. The computational cost increases linearly with the number of transmitting sources.
Waveform tomography accounts for all the wave propagation effects, and is more powerful than diffraction tomography. It is usually carried out with a numerical simulator and is capable of properly handling complex wave phenomena. However, ultrasound waveform tomography is computationally expensive for data acquired using a synthetic-aperture ultrasound tomography system, particularly for three-dimensional imaging. Ultrasound waveform tomography numerically calculates sound-wave propagation from every ultrasound transducer element. In a synthetic-aperture ultrasound tomography system, hundreds to thousands of transducer elements emit ultrasound, which requires an enormous amount of computational time and resources for ultrasound waveform tomography
Ultrasound waveform tomography could become a high-resolution imaging approach for breast cancer detection and diagnosis. The main disadvantage of ultrasound waveform tomography is too computationally expensive to be feasible for clinical applications, particularly for large datasets acquired using a synthetic-aperture ultrasound tomography system that consists of hundreds to thousands of transducer elements.